P. I. P. E. Flashcards
- The specific volume of steam at atmosphere pressure and 2.12 F is 26.80 ft^3/lb. Find ( (a) its -density and (b) its specific weight.
A. 0.03731 lb/ft^3 or 0.598 kg/m^3
B. 0.03731 lbf/ft^3
- f the density of mercury is 13,600 kg/m^3, find (a) its density in lb/ft^3 and (b) its specific weight in N/m^3.
A. 849.0 lb/ft^3
B. 133,416 N/m^3
- A pressure gauge connected to a turbine inlet reads 400 psi. A vacuum gauge connected in the exhaust trunk of the same turbine reads 28.0 in. Hg. The barometer reads 30.1 in. Hg. Find: (a) the absolute pressure the turbine inlet, psia, and (b) the absolute pressure in the turbine exhaust trunk, in. Hg. abs.
A. 414.8 psia
B. 2.1 in. Hg. abs
- The mercury level in the vertical tube is exactly 760 mm above the mercury level in the reservoir (y = 760.000 mm). the following data also, apply: “water” and “mercury” can be considered to be incompressible fluids having densities of 1000 kg/m^3 and 13,595.1 kg/m^3, respectively. The standard acceleration of gravity is equal to 9.80665 m/sec?. Find:
A. In.Hg.
B. ft.H20
C. Pascals, Pa (N/m^2)
D. lbf/ft^2
E. Psi (lbf/in^2)
Ans. 29.92 in Hg
Ans. 33.90ft H20
Ans. 101325.014 Pa
Ans. 2116.8 lbf/ft^2
Ans. 14.7 psi
9 . If the difference in height of the water legs in the open manometer is 20 in. (dimension y), find the absolute pressure at point A in psia. The specific weight of water is 62.4 lbf/cu ft.
15.42 psia
- In the differential manometer points A and B are the at the same height. The mercury used as a manometric fluid stands 9 inches higher in the B leg than in the A leg (y = 9 in.). find the diference in pressure between points A and B in psf. Specific weight of mercury is 849 lbf per cu ft.
590 lb/ ft^2
- Steam is flowing in a pipe at a velocity of 100 ft/sec. What is the associated kinetic energy per pound of steam flowing?
155.28 ft-lb/ lb or 0.20 Btu/ lb
- The work delivered by a turbine is 400 Btu per lb of steam supplied when the steam flow is 20,000 lb per hour. Find:
A The specific work in ft. Ibf/ lb
B. The power delivered in hp
C. The power delivered in kW
Ans. 311,200 ft-lb/ lb
Ans. 3143 hp
Ans. 2344 kW
- A steam turbine receives steam at 1379 kPa gauge and exhausts it to a condenser where the vacuum is indicated as 635 mm of Hg by a gauge. For a barometric pressure of 760 mm of Hg, calculate (a) the absolute pressure at the turbine inlet, kPa, and (b) the absolute pressure corresponding to the vacuum gauge reading kPa, and mm of Hg.
A. 1480 kPa
B. 16.7 kPa and 125 mm Hg
- A boiler feed pump takes water at an elevation of 10 feet above a chosen datum and pumps it into a boiler drum at elevation 30 feet. Calculate the change in potential energy for the water from pump to boiler in (a) ft. Ibf/ lb, and (b) Btu/lb.
A. 20 ft. lbf/ lb
B. 0.0257 Btu/ lb
- High pressure steam enters a turbine with a velocity of 125-ft/sec. and leaves the exhaust trunk of the turbine with a velocity of 1000 ft/sec. Calculate the kinetic energy of the steam in ft. Ibf/ lb and Btu at (a) the entrance to the turbine, and (b) the exhaust trunk.
A. 242.6 ft.lbf/lb, 0.312 Btu/lb
B. 15,530 ft.lbf/lb, 19.96 Btu/lb
- High pressure steam enters a turbine with a velocity of 38.0 meters/sec. and leaves the exhaust trunk with a velocity 305 meter/sec. Calculate the kinetic energy of the steam in kJ/kg and N. m/kg at (a) the entrance to the turbine and (b) the exhaust trunk.
A. 0.722 kJ/kg, 722 N.m/kg
B. . 46.5 kJ/kg, 46,500 N.m/kg
- Feed water enters a boiler drum at 700 psia, 300 F and a specific volume of 0.0174 ft^3/lb. steam leaves the superheater of the boiler at 600 psia, 550 F and a specific volume of 0.8749 ft^3/lb. Calculate (a) the flow work in Btu/lb associated with the water entering the boiler drum, and (b) the flow work in Btu/lb associated with the steam leaving the superheater.
A. 2.25 Btu/ lb
B. 97.2 Btu/ lb
- Feed water enters a boiler drum at a pressure of 4826 kPa abs, 148.9 C and a specific volume of 0.00109 m^3/kg. steam leaves the superheater of the boiler at 4137 kPa abs, 287.8 C and a specific volume of 0.0546 m^3 /kg. Calculate (a)the flow work in kJ/kg associated with the water entering the boller drum, and (b) the flow work in kJ/kg associated with the steam leaving the superheater.
A. 5.26 kJ/kg
B. 225.9 kJ/kg
- A small air compressor delivers 1 lb per min of air while supplying 3 horsepower to the air. Calculate the specific work, ft.lbf/lb, supplied to the air.
99,000 ft.lbf/lb
- A steam turbine develops 200 horsepower while receiving 400 Btu from each pound of steam passing through the turbine. Calculate the pounds of steam per hour required by the turbine to produce this power.
Ans. 1272.5 lb/hr
- A steam turbine develops 149 kW while receiving 930 kJ from each kilogram of steam passing through the turbine. Calculate the kilograms of steam per hour required to produce this power.
576.8 kg/hr
- Many marine steam propulsion plants achieve a fuel rate of 0.45 pound of fuel per shaft horsepower hour. Determine the equivalent fuel rate in kilograms per shaft kilowatt hour.
0.27 kg/kW.hr
- A certain mountain location where the barometer reads 13.5 psia, the intake manifold gauge on a cross-country truck reads 20 inches of mercury vacuum. Calculate the absolute pressure in the truck intake manifold, psia and in. Hg.
3.7 psia or 7.5 in. Hg
24, The power delivered by an auxiliary turbine is 500,000 Btu/hr when the steam flow is 4000 lb/hr. Find (a) specific work, ft.lbf/lb, and (b) the power delivered, hp.
A. 97,250 ft.lbf/lb
B. 196.5 hp
- A working substance enters a thermodynamic steady flow system with the following conditions: p1 = 20 psia, v1= 11.7 ft^3/lb, u1 = 101.6 Btu/lb, V1= 150 ft/sec. The working substance leaves the system with the following conditions: p^2= 25 psia, v^2= 10.3 ft^3/lb, u = 149.0 Btu/lb, and V^2= 500 ft/sec. Changes in elevation through the system are negligible, and 10 Btu/lb transferred heat is added to the fluid as it passes through the system. Determine the work done on or by the fluid, Btu/lb.
(-) 46.3 Btu/lb (on)
- In a certain non-flow process, the internal energy decreases 20 Btu/lb, and 77,800 ft.lbf/lb of work is done on the substance. Find the heat added or abstracted.
120 Btu/lb (abstracted)
- Another non-flow process involving 2 kg of working substance there is no heat transferred, but the internal energy increases 5000 joules. Find the work done on or by the substance, J/kg.
(-) 2500 J/kg (on)
- At pressure of 100 psia and 400 F, the specific volume of steam is 4.934 cu ft/lb, and the specific enthalpy is 1227.5 Btu/lb. Find the internal energy at the given state, Btu/lb.
1136.18 Btu/lb